. >> thousands of people marched on the national mall in washington yesterday, braving a cold winter wind to take part in what organizers called the biggest climate rally in u.s. history. they called for president obama to reject the proposed keystone excel oil pipeline. >> the reason i came here today was because i feel like president obama... i feel like if we make a statement with our numbers and our passion that he'll get the message. >> woodruff: the keystone project is designed to move crude oil hundreds of thousands of barrels a day that would be extracted from the oil sands of northern alberta in western canada. the oil would be transported across several u.s. states to refinerees and ports in texas. the company behind the 1700-mile pipeline, trans-canada, has altered the route to largely by-pass a water deposit in nebraska. but protest organizers insisted the pipeline still threatens land it crosses and will mean even greater carbon pollution. >> the president needs to think about what his legacy is going to be. 50 years from now, no one is going to care about the fiscal cli